Power to various components of an electronic system (such as a computer system or other type of electronic system) is provided by a power supply in the electronic system. The power supply includes a power source that can be an alternating current (AC) source, such as that provided by a wall power outlet. The input of the AC power source is provided to an AC power adapter, which produces a direct current (DC) power voltage to the electronic system. Another type of power source is a battery, which provides one or more DC power voltages for the electronic system.
The power supply of an electronic system includes one or more DC-DC converters for converting an input DC voltage (such as that provided by a battery or by the AC power adapter) to one or more other power voltages that are provided to the components of the electronic system.
In some sophisticated electronic systems, such as high-end servers with multiple processors or processor modules, a power supply includes multiple power modules for redundancy. For example, an electronic system can include two power modules, each with its own set of converters and related circuitry. In a power supply with redundant power modules, if any one of the power modules fails, the remaining power module(s) can continue to supply power to the electronic system to enable continued operation of the electronic system.
If a power module should fail, then the power module containing the failed converter can be pulled out of the electronic system while the other power module(s) continues to supply power to the electronic system. The ability to replace power modules while the electronic system remains live is enabled by using hot-swappable power modules. A hot-swappable power module is a power module that can be removed from the electronic system while the electronic system remains powered on. Also, a hot-swappable power module can be inserted into the electronic system while the electronic system remains powered on.
During normal operation of an example electronic system having two identical power modules, each of the two power modules provides about half of the power to the load in the electronic system. As one or more converters start failing, then the remaining converters of both power modules compensate for the failed converter(s) by driving more power to the load. However, if one of the power modules has to be removed for replacement, then a sudden drop in the power supplied to the load will occur. Although the remaining power module of the electronic system can compensate for the removed power module, the remaining power module is typically unable to react fast enough to the sudden drop in supplied power. The sudden drop in the power supplied to the load as a result of the power module being removed can cause the output voltage provided by the remaining power module to dip before a full recovery can occur. The voltage dip can cause certain components in the electronic system to shut off, which may cause a crash of the electronic system. Low-voltage components, such as those that operate at 1.5 volts, for example, are especially susceptible to voltage dips caused by hot swapping of power modules.
If the electronic system is a server in a network environment, for example, a crash of the server due to the hot swapping of a power module would make the server at least temporarily unavailable. The temporary unavailability of the server means that data and services provided by the server would become inaccessible by users in the network environment.